Raptors have lost six straight first-round series-openers under Dwane Casey

Giannis Antetokounmpo scores 28 points as the Bucks shut down the Raptors 97-83 in the series opener.

TORONTO -- Maybe the Toronto Raptors lost Game 1 because they always lose Game 1.

The Milwaukee Bucks' 97-83 win at the Air Canada Centre on Saturday was the Raptors' ninth straight loss in a Game 1 of a playoff series. They're 0-6 in Game 1s under head coach Dwane Casey and five of those games were at home.

It's a wacky streak, only outdone by the Chicago Bulls' success on Thursday TNT games in regard to being inexplicable. But the Raptors are not down 1-0 in this first-round series because of what's happened in previous years. They're down 0-1 because of what happened on the floor Saturday night, when they scored a paltry 31 points on 45 possessions in the second half.

That's a brutal number for an offense that led the league in efficiency through mid-January and finished sixth for the season. The Raptors also had a top-10 defense, but the two ends of the floor are linked. Success on one end leads to an easier possession on the other, and when you don't score against the Bucks, you allow them to run.

The Bucks' success began with increased effort and energy on defense. Milwaukee can always bother the opposing defense with its length and athleticism. But when that length and athleticism is combined with energy and multiple efforts, it takes a special kind of discipline to get good shots.

It's about more than just the ball-handler's willingness to give up the ball, because the Bucks will meet the first pass with another defender. It's about the second or third pass finding the open man quickly enough so that the Bucks pay for their initial aggressiveness.

The Bucks' defense will give up good shots if you have that kind of response. No team allowed its opponents to take a higher percentage of their shots from the restricted area or 3-point range in the regular season, when Milwaukee ranked 19th on that end of the floor.

In the second half of Game 1, the Raptors could not take advantage of the Bucks' scheme. They shot 7-for-35 after halftime, with as many turnovers (seven) as made shots. After scoring 32 points in the paint in the first half, the Raptors scored just four in the second half.

"The second half was abysmal," Casey said afterward. "We didn't play with any pace, any rhythm, any movement. Have to give them credit. They did a good job defensively."

DeMar DeRozan scored 18 points in the first half before the Bucks stepped up on defense.

Indeed, the Bucks deserve more credit than the Raptors deserve blame. Milwaukee's energy and effort dictated the second half. Even when the Raptors moved the ball and attacked quickly, the defense was there. When DeMar DeRozan and Kyle Lowry got to the basket in the second half, they were met by the long arms of Thon Maker or Giannis Antetokounmpo. The Raptors shot 2-for-10 at the rim after halftime.

"Our defense was up to par this evening by just playing hard," Bucks coach Jason Kidd said. "We're a young team and it starts with playing hard and trusting one another. They did that this evening."

Maybe the Bucks were the team just waiting until the playoffs to flip the switch defensively. If they continue to play the way they did in the final 24 minutes on Saturday, the Raptors -- arguably the best Toronto team we've ever seen -- have a serious challenge on their hands.

The question is if it's in the Raptors' DNA to take advantage of the kind of defense they're facing. This team is not the 2014 San Antonio Spurs when it comes to ball and player movement. The Raptors assisted on just 47 percent of their baskets this season, the lowest assist rate for any team in the last 13 years. Their strength is the ability of their guards to get buckets off the dribble. But that kind of offense can play into the hands of a defense like Milwaukee's.

The Bucks know this and the Raptors knew what was coming on Saturday. This is how Milwaukee defended them in the regular season. But Toronto couldn't overcome the extra energy in Game 1 and they'll need to be better in Game 2 on Tuesday to avoid a 2-0 deficit.

"Once the ball gets in the half-court, we have to get better movement, exchanges," Casey said. "Don't stand there and help their defense. All of that led to tough shots, challenged shots, and we were totally out of rhythm in the second half."

We've seen this before. Each of the last two years, the Raptors have suffered huge drop-offs in offensive efficiency in the playoffs, as opponents have taken away what has worked in the regular season. But the DNA isn't going to change overnight.

"I don't know if we have to be a high-assist team," Casey said. "I don't know if you're going to change Kyle's personality, DeMar's personality to become an assist guy. Now, if they have two bodies on them, yes. They have to give it up and make it a play. But we're not going to change who we are totally."

Maybe it's more about playing better than playing differently. Sometimes the best adjustment is making shots. But better shots will come with better execution, better discipline and better cohesion. And if the Raptors just don't have what it takes to take advantage of an aggressive defense, their Game 1 streak will run into Game 2.